Abstract: A joint pin seal for a caterpillar track. The join pin seal comprises a support ring of hard elastomer material having a cylindrical inner wall. The support ring is firmly pressed in a housing bore which is adjacent a relatively movable machine part to be sealed. The support ring comprises a stiffening ring contacting the rear wall of the housing bore and a lip ring adjacent the machine part to be sealed. The lip ring has a sealing lip which presses against the surface of the machine part to be sealed. The stiffening ring is tapered in notch-like fashion into said lip ring forming a membrane at the transition into the lip ring and provides the support ring with a notch between the lip ring and the stiffening ring. A pressure ring, formed from a softer elastomer material, is disposed within the notch and contacts the housing bore wall. The pressure ring presses the sealing lip into the relatively movable machine part to be sealed.